1. Technology Field
The present invention generally relates to optical transmitters and receivers. In particular, the present invention relates to an optical subassembly that is configured to eliminate problems relating to hard plugging, fiber wiggle, and shavings when connecting with an optical fiber.
2. The Related Technology
Optical transceivers are used to transmit and receive optical signals from an optical network and to enable electrical network components to interface with and communicate over optical networks. Many optical transceivers are modular and are designed in accordance with industry standards that define mechanical aspects of the transceivers, form factors, optical and electrical requirements, and other characteristics and requirements of the transceivers. For example the Small Form-Factor Module Multi-Source Agreement (“SFF MSA”), the Small Form-Factor Pluggable Module Multi-Source Agreement (“SFP MSA”) and the 10 Gigabit Small Form Factor Pluggable Module Multi-Source Agreement (“XFP MSA”) Revision 3.1 define such standards.
The basic optical components of conventional transceivers include a transmitter optical sub-assembly (“TOSA”) and a receiver optical sub-assembly (“ROSA”). The TOSA receives electrical signals from a host device via circuitry of the transceiver module and generates a corresponding optical signal that is then transmitted to a remote node in an optical network. Conversely, the ROSA receives an incoming optical signal and outputs a corresponding electrical signal that can then be used or processed by the host device. Additionally, most transceivers include a rigid printed circuit board (“PCB”) containing, among other things, control circuitry for the TOSA and ROSA.
The TOSA and ROSA are each connected to the optical network via optical fibers that are capable of transmitting optical signals. Each optical fiber includes a connector that mates with a corresponding port defined in the respective TOSA or ROSA.
Various challenges have been known to arise when connecting connector-equipped optical fibers with TOSA and ROSA ports. One of these challenges is referred to “hard plug,” a condition in which difficulty is encountered when attempting to insert or remove the optical fiber connector to and from the port. This condition can be caused by several factors, including the port being formed of a material, such as zinc or aluminum, that are relatively soft when compared to the connector material, which can cause deformation of the relatively softer port material when the connector is repeatedly inserted and removed from the port. Other port materials, such as nickel may migrate while the connector is plugged into the TOSA or ROSA port, which can also cause hard plug.
To alleviate hard plug problems, some OSA port designs have employed a split sleeve that is inserted into the port to define the contact surface for the port when the optical fiber connector is inserted therein. The sleeve is longitudinally split along its length so that it flexes slightly when the optical fiber connector is inserted into or removed from the port, thereby reducing hard plug. Such port designs, however, are also known to poorly perform when subjected to a “wiggle” test, wherein the optical fiber is grasped and wiggled while its connector is received within the TOSA or ROSA port and variance in the optical coupling and optical power between the fiber and the TOSA or ROSA is measured. Because of its tendency to flex, the OSA port having a split sleeve design enables substantial movement of the connector within the port. This, in turn, can significantly reduce the optical power transmitted between the optical fiber and the TOSA/ROSA. As many vendors require certain levels of wiggle performance, problems in this area can represent a serious problem for manufacturers. Moreover, it is noted that split sleeve portion designs often require the insertion of a fiber plug therein, thereby necessitating further process steps and assembly cost.
In yet another attempt to solve hard plug issues, the optical subassembly body that defines the port has been manufactured out of relatively hard materials that will not deform or otherwise be compromised when connector insertion or removal is performed. However, manufacture of an optical subassembly from such materials is relatively expensive, both in terms of the cost of the materials and the process needed to manufacture the part. In the current competitive environment where costs are constantly being driven downward, such solutions quickly become untenable.
Other problems can arise with materials and designs previously used for TOSA and ROSA port configurations. These problems include the production of shavings from the port surface when the connector is inserted, and corrosion of the port material due to high iron content. Also, many of the above configurations require labor intensive procedures to prepare the optical subassembly and the port, including precision machining and boring, plating, repetitive process steps, etc.
In light of the above discussion, a need exists in the art for an optical subassembly that includes a port for operably connecting the connector of an optical fiber. Moreover, a need exists for an optical subassembly port that does not suffer from hard plug upon either insertion or removal of the optical fiber connector into or form the port. Any solution should also exhibit acceptable wiggle performance, reduce the incidence of shaving production within the port, and should reduce overall costs of subassembly production.